fix(prefix): fix bug when buffer realloc occurs during prefix lookup #61
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Luacheck Report2 tests ±0 0 ✅ ±0 0s ⏱️ ±0s For more details on these failures, see this check. Results for commit d66f376. ± Comparison against base commit 890b3ca. ♻️ This comment has been updated with latest results. |
chronolaw
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Prefix based lookup may need to reallocate the key/value buffer when the buffer size exceeds the default (currently 1MB). However, because we use the `ops[0]` and `ops[1]` passed in is used for both providing the `after` and `prefix`, in case of `NGX_AGAIN`, these will be overwritten by the `ngx_lua_resty_lmdb_ffi_prefix()` function to the first and second key respectively, which breaks the retry and causing the second call to `ngx_lua_resty_lmdb_ffi_prefix()` to return empty. This commit fixes the above issue by always resetting `ops[0]` and `ops[1]` between retries, therefore the above issue no longer occurs. Also, this commit fixes a use-after-free bug for `db_drop()` operation when map is full.
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StarlightIbuki
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Prefix based lookup may need to reallocate the key/value buffer when the buffer size exceeds the default (currently 1MB).
However, because we use the
ops[0]andops[1]passed in is used for both providing theafterandprefix, in case ofNGX_AGAIN, these will be overwritten by thengx_lua_resty_lmdb_ffi_prefix()function to the first and second key respectively, which breaks the retry and causing the second call tongx_lua_resty_lmdb_ffi_prefix()to return empty.This commit fixes the above issue by always resetting
ops[0]andops[1]between retries, therefore the above issue no longer occurs.Also, this commit fixes a use-after-free bug for
db_drop()operation when map is full.KAG-5874